The present invention relates to an improved process for preparing dialkanesulfonyl peroxide (RSO.sub.2 --O--O--O.sub.2 SR) continuously by electrolysis of the corresponding alkanesulfonic acid at an elevated temperature.
Dimethanesulfonyl peroxide ("DMSP") was first produced by Jones and Friedrich [U.S. Pat. No. 2,619,507] by the batchwise electolysis of a 10.2N solution of methanesulfonic acid in water using shiny platinum plate electrodes at a current density of 0.2 amp/cm.sup.2. This approach resulted in deposition of the DMSP on the anode and a poor current yield (less than 20%). Deposition of the peroxide on the electrodes also resulted in explosive decomposition in subsequent preparations of DMSP [R. N. Haszeldine, R. B. Heslop, and J. W. Lethbridge, J. Chem. Soc., Part A, 4901-7 (1964)]. Myall and Pletcher [C. J. Myall and D. Pletcher, J. Chem. Soc., Perkin Trans, 1 (10), 953-5 (1975)] produced DMSP by batchwise constant current electrolysis of a solution of sodium methanesulfonate in anhydrous methanesulfonic acid in a divided electrolysis cell. This method resulted in improved (63%) current yields, but it requires preparation of sodium methanesulfonate and recovery of the product peroxide requires extensive (5:1) dilution of the aqueous methanesulfonic acid using water. In addition, divided electrolysis cells are significantly more costly than undivided cells.